The invention is related to the field of managing computer data storage systems.
Computer data storage systems have evolved into complex arrangements of specialized elements that are coupled together, such as in a modern storage-area network (SAN). A SAN, for example, includes host computers running application programs with storage requirements, such as for file systems and databases. The SAN further includes dedicated storage devices, often termed “arrays”, that are packaged into cabinets and are physically and functionally separate from the host computers. The hosts and storage devices are coupled together by a high-speed data network which includes transmission lines and switches.
Because of the complexity and size of SANs, specialized software tools are used to assist a storage system administrator in managing the configuration and operation of the SAN. An example of such storage management tools includes a suite of tools known as “EMC Control Center” sold by EMC Corporation. These tools include a wide variety of management-related features, including controls that enable a system administrator to configure storage and establish channels between the hosts and respective storage devices allocated for use by the hosts, and include monitoring functions for gathering many types of information about system operation, including for example the amount of allocated storage actually used by the respective hosts, the amount of storage traffic flowing through switches or into/from storage devices, the presence of faults or other reportable conditions in the system, etc.
As with expensive capital assets in general, it is necessary to account for the use of storage systems so that costs are correctly allocated among users having separate budgets, whether the users are from separate companies or are sub-units (e.g. departments) of a single company. In the case of single-company users, the assessing of costs to individual department or other sub-units is referred to as “chargeback”. Accounting systems can be used for such chargeback purposes, for example. However, accounting systems are often limited to relatively simple models of system use, which can adversely affect the accuracy of any cost allocation scheme. The actual costs of storage system assets may be much more complex and difficult to model accurately from a cost perspective. It may be exceedingly difficult or impossible to accurately reflect subtle aspects of storage system structure or use in a simple accounting-oriented model, leading to the undesirable possibilities of over-charging as well as under-charging system users.